This invention relates to an ignition distributor rotor for suppressing radio frequency interference electromagnetic radiation. More particularly, this invention relates to an ignition distributor rotor having an output electrode coated with a polyester and a polyamide-imide varnish for suppressing such radiation.
There has been considerable effort to modify automotive distributors so that the electrical discharge between the distributor rotor electrode and a corresponding spark plug lead terminal does not generate radiation that interferes with radio reception. For example, it has been proposed to place a resistive or semiconductive element at the tip of the distributor rotor electrode to suppress radiation of radio frequency. It has also been a practice to coat the output segment of a distributor rotor with silicone varnish. Such use of the varnish does effectively reduce radio interference, but the material is relatively expensive and not easily applied to the brass electrode. The art has now developed to the point where there is a need for an inexpensive and easily manufactured distributor rotor electrode that matches or surpasses the performance of the above described practices.
It is an object of the present invention to provide a distributor rotor output electrode that is highly effective in suppressing radio frequency interference. Furthermore, the electrode is easy and inexpensive to manufacture.
It is a more specific object of the present invention to provide a distributor rotor output electrode provided with a coating of polyester and polyamide-imide resins such that, in operation of the distributor, radio interference is reduced to required levels.